1. The effects on the development of the T-cell repertoire of anti-Ia antibody administration. 2. The effects of anti-Ia antibodies on normal and tumor bearing adult mice. 3. The mechanism of thymic determination of MHC restriction of T lymphocyte antigen recognition. 4. The physiology of HTLV-1 transformed B lymphocytes. 5. The development and characterization of monoclonal antibodies to Reed-Sternberg cells.